How Long Does Weed Stay in Your System?

Metabolism is a constantly occurring process within every cell of your body. It is necessary to maintain life. Our body metabolizes everything we put in it whether it’s life-sustaining or not. For instance, your body metabolizes the THC in marijuana. Marijuana metabolites stow away in your body anywhere from a few days to over a month. How come weed stays in your system so long?

The marijuana drug test is one of the oldest and most commonly used tests. However, legalization is keeping it under the spotlight. Legalization poses an interesting challenge for employers, with some choosing to begin testing for marijuana use, and others choosing to stop. Advocates for legalization, of course, call for entirely removing it from company drug testing.

Reasons to conduct a marijuana drug test

A documented drug testing policy is designed both to protect the company from liability and to educate employees on what’s expected. This drug policy should be fair and reasonable, clearly stated, fully explained, and compliant with all applicable laws at the local, state, and federal level, in the locations where the company has employees.

Failing to do this may result in invalidated test results and possibly even an HR-related lawsuit. Fortunately, following a written drug testing policy eliminates these situations. It may include any or all of the following drug testing requirements.

Pre-employment drug test

As one of the most common reasons to perform a drug test, a pre-employment drug test is intended to weed out potential employees who use marijuana. This helps employers to avoid problem employees in the first place.

Random drug test

A random drug test ensures that employees did not merely refrain from drug use during the applicant phase. It also helps to maintain higher workplace productivity, morale, and safety because employees know they are subject to a drug test at a moment’s notice. The Department of Transportation requires yearly drug tests, but some companies conduct quarterly or even monthly random drug testing.

Post-accident drug test

Immediately after an accident, an employer may conduct (or may be required to conduct) a post-accident drug test. In addition to regulatory and/or workers comp insurance reasons, this also discourages drug use since employees know they can be tested if they are involved in a workplace accident.

Reasonable suspicion drug test

A reasonable suspicion drug test may be conducted if a supervisor suspects drug use based on appearance, behavior, speech, smell, and other indicators. Your drug testing policy must clearly document these indicators.

Return to duty

After a positive drug test result, the DOT requires a return to duty drug test before an employee returns to a safety-sensitive role. This is intended to ensure the employee has not consumed any drugs since the last drug test.

DOT drug test

Employers bound by Department of Transportation regulations must conduct a DOT drug test in specific situations. As opposed to non-DOT employers, this is not optional and must be conducted according to DOT regulations.

Differences in detection

Standard drug panels, which include 5 panel, 10 panel, 12 panel and DOT drug tests, all include marijuana. In other words—unless specifically removed, any test could be considered a marijuana drug test.

Drug tests detect the metabolites left behind after metabolism occurs. When THC completes the process, it produces a metabolite named tetrahydrocannabinol carboxylic acid (THC-COOH). The metabolites store themselves throughout the body. Mainly, though, they house themselves in the fat cells.

Detection periods vary depending on the testing method.

Urine test

The most frequently used employee drug test is the urine test. Employers choose them for many reasons. They are cost-efficient, extremely accurate, and expected. When an employee hears the words “drug test,” they usually assume a urine test is coming up.

Someone who rarely uses marijuana in any form is likely to pass a urine drug test after three days. This is because the amount of THC-COOH stored throughout the body has either dissipated or is not exiting the body at levels high enough to register.

A moderate user, someone who ingests THC up to four times a week, will test positive for up to five days. It makes sense that if the body stores THC-COOH, the more often one uses it, the greater the number of metabolites stored away in the body. Therefore, tests detect them for a longer period of time.

Par for the course, a daily marijuana user will test positive for up to ten days after discontinuing use. The cleansing process is constant so refraining from marijuana use allows your body to excrete the THC metabolites after this period of time.

Lastly, someone who is a chronic marijuana user is likely to test positive for thirty days or longer. This also stands to reason because the body is constantly retaining THC-COOH. Again, the more often one uses, the greater the number of metabolites stored.

Saliva drug tests

Recent advances in technology coupled with a detection window of up to 72 hours make the mouth swab test a solid choice for those who want to determine recent drug use.

For that reason, employers and law enforcement agencies use this test more than ever before.

Hair follicle drug test

The hair follicle drug test creates a permanent record of drug use. This is because the drug metabolites that store themselves in the hair follicle grow out and become part of the hair itself. These tests are extremely accurate and there is virtually no way to falsify the results.

Employers use the hair follicle tests the least. The cost factor is likely a big contributor to that fact. These days, though, many employers are taking a second look.

The test determines if there was any marijuana use over a period of ninety days. However, if someone has used the drug for the first time within a week of testing, it’s possible that they will obtain a negative test result. It takes a few days for the metabolites to show up because they need time to grow out of the hair follicle and into the hair shaft.

However, once it’s there, it’s there for good.

Blood drug test

If you smoke weed, THC enters your bloodstream within seconds of inhaling it. Edibles take a bit longer as they go through the digestion process before entering the bloodstream.

Blood tests aren’t used very often when testing for marijuana though. That’s because the detection period is extremely short-lived. Typically, THC remains in the bloodstream for just three to four hours.

Why do detection times vary?

We hit on the fact that the more you use, the greater the number of THC-COOH metabolites that are stored throughout your body. Moreover, there are other contributing factors to consider regarding detection times.

THC levels

Specifics play a part

An individual’s metabolism is another determining factor. For whatever reason, one person tests positive longer than another. It has to do with the way each body metabolizes the drug. Being in shape makes a difference. THC-COOH mainly collects in the fat cells. Thin people don’t have as many fat cells. If you are overweight, the likelihood increases that there is a virtual warehouse full of the stuff!

Impairment issues

Cannabis has psychoactive and physiological effects when consumed. Aside from a subjective change in perception and, most notably, mood, the most common short-term physical and neurological effects include increased heart rate, increased appetite, and consumption of food, lowered blood pressure, impairment of short-term and working memory, psychomotor coordination, and concentration. Long-term effects are less clear.

While many psychoactive drugs clearly fall into the category of stimulant, depressant or hallucinogen, cannabis exhibits a mix of all properties, perhaps leaning the most towards hallucinogenic or psychedelic properties, though with other effects quite pronounced as well.

Marijuana (cannabis) is consumed in many different ways, most of which involve inhaling vaporized cannabinoids (“smoke”) from small pipes, bongs (a portable version of a hookah with a water chamber), paper-wrapped joints or tobacco-leaf-wrapped blunts. Alternatively, the cannabis plant flowers may be finely sifted producing kief, a powder especially rich in the oil-glands or trichomes which contain the highest amounts of cannabinoids.

When someone smokes marijuana, impairment occurs almost immediately. The THC passes from the lungs directly into the bloodstream. Once in the blood, it races to the brain and other organs throughout the body. The “high” peaks in about an hour, and lasts for several hours.

Edibles, on the other hand, often take several hours to reach the height of impairment. The user begins to feel the effects of the drug about 30 minutes after consumption. They are “back to normal” after about five hours.

They say it’s not addicting

Cannabis can be habit-forming and the development of cannabis dependence in some users has been well established; its effects on intelligence, memory, respiratory functions and the possible relationship of cannabis use to mental disorders such as schizophrenia, psychosis, Depersonalization disorder and depression are still under discussion.

Short-term

The sense of euphoria that accompanies smoking pot is due to the release of dopamine in the brain. During the hours of impairment, users experience any or all of the following.

an altered sense of time

changes in mood (often described as mellow)

impaired body movement

difficulty with problem-solving and focus

impaired memory

In the case of a very high dose of THC, hallucinations, delusions or even psychosis can occur.

Also alarming, some studies show that chronic users exhibit motor skill impairment for days or weeks after discontinuing use.

Long-term

Studies have shown that people who smoked marijuana heavily in their teens and continued heavy use into adulthood lost an average of 8 IQ points before they were forty. However, those who began smoking as an adult did not show a decline in IQ.

There are studies that show that people who smoked the drug heavily in their teens suffer from impaired thinking, learning, and memory skills. It appears that the drug affects how the brain builds the connections necessary to complete these tasks.

It’s unclear, however, if this is caused by the THC itself or predisposition factors in the DNA.

It’s CBD not THC

By the way, this is especially true if someone took it just before a drug test. They may test positive for the test but take a test later in the day with a negative result. By the way, we conducted an in-house test of our own that produced this result. Moreover, the CBD product our volunteer took advertised that it was THC free!

There are testing measures in place to regulate the extraction process. Therefore, it is impossible to ensure that THC levels fall under a specific range. If products promoting zero amounts of THC contain enough to produce a positive test result, it stands to reason that any CBD product warrants a risk of a positive test result.

It might be a good idea to educate your employees in regard to this information. The outcome could be that employees rethink the decision to use CBD for medicinal purposes.

Weeding through it all

In a tightening labor market, some employers believe the incentive to test less looks enticing as marijuana drug testing does have a cost, and, if it’s legal, why bother? This thinking, however, ignores the safety and productivity impact of marijuana use. For companies operating in multiple states, inconsistency regarding law-making creates problems with standardization of compliance policies company-wide.

Furthermore, marijuana use is still illegal at the national level.

That said, however, our society has deemed pot to be a harmless drug. As a result, its use is becoming more and more widely accepted. Still, employers have every right to remain concerned.

No matter how they consume it, employees under the influence of marijuana usually become less productive. More importantly, it’s a proven fact that motor and cognitive skills are affected, possibly for an extended length of time. There is no doubt that marijuana users increase their chances of causing workplace accidents.

In the long run, it is much more cost-effective to maintain a drug-free workplace. In order to avoid the effects of marijuana use, it is critical to have a clearly defined workplace drug testing policy, including employee and supervisor education, testing protocols, repercussions for drug use.

Drug testing in the workplace deters some from choosing a lifestyle that includes smoking weed. Routine reminders of your company drug policy or on-site refresher courses regarding the dangers of drug use act as further deterrents.

Much like the process of metabolism that goes on within every cell of our bodies, promoting a drug-free workplace is an ongoing process. In the same fashion, just as metabolism is necessary for sustaining life, educating your employees about the dangers of taking drugs could sustain a life too.

Do you need a drug test conducted at a certain date and time? Call us at and we will dispatch a mobile collection specialist to administer your drug tests at any location, 24 hours a day, 7 days a week.

Are you looking for more information about drug testing, a drug free workplace program, or compliance? Call us at and we'll be happy to answer any questions you may have and tailor a program to your specific needs.